The issue before the court is whether the United States Trustee ("UST") fee, created by amendment of 28 U.S.C. § 1930(a)(6), should apply to cases with substantially consummated liquidating plans allocating all estate assets to creditors, which were confirmed prior to the amendment's January 26, 1996 effective date. Bankruptcy Code § 1127(b) prohibits modification of the confirmed plan advocated by the UST, and it prohibits modification of substantially consummated plans. The court is prevented from ruling that these debtors owe quarterly fees as of January 26, 1996, by application of the presumption against statutory retroactivity articulated in Landgraf v. USI Film Prods., 511 U.S. 244 (1994). The amendment's plain language does not indicate that the fees apply to cases confirmed prior to the date of its enactment, and the legislative history does not clearly support that Congress intended such a result. The court concludes that the amendment is impermissibly retroactive as applied to these cases, and that the UST's fees cannot be assessed and collected in Chapter 11 cases with liquidating plans allocating all estate assets to creditors, which were confirmed and substantially consummated prior to the effective date of the Amendment.